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Finding the Fourth Proportional to 431.61, 647.31 and 139.04

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Solution

The fourth proportional to 431.61, 647.31 and 139.04 is: 208.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.61 : 647.31 = 139.04 : x
  2. Step 2: Convert to fraction form
    431.61/647.31 = 139.04/x
  3. Step 3: Cross multiply
    431.61x = 647.31 × 139.04
  4. Step 4: Simplify right side
    431.61x = 89,998.75
  5. Step 5: Solve for x
    x = 89,998.75/431.61
  6. Step 6: Final answer
    x = 208.52

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.